Electric heater for fans.



A. SGHAEPFER.

ELECTRIC HEATER FOR FANS.

APPLICATION FILED APB.8, 1912.

1,106,975. Patented Aug-11, 191

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AUGUST SCHAEFFER, OF FRANKFORT-ON-THE-MAIN, GERMANY.

ELECTRIC HEATER FOR FANS.

Specification of Letters Patent.

. Patented Aug. 11 1914.

Application filed April 8, 1912. Serial No. 689,126;

To all whom it may concern:

Be it known that I, AUGUST SoHAErrEn, engineer, a citizen of the German Empire, and resident of Moselstrasse No. 40, F rankfort-on-the-Main, Germany, have invented certain new. and useful Improvements in Electric Heaters for Fans; and I do hereby declare the followin to be a full, clear, and exact description of the invention, such as will enable others skilled in the art towhich it appertains to make and use the same.

Electrically driven hot and cold air douches have a disadvantage which has not been overcome up to the present, namely such apparatus have to be built for a particular voltage. An apparatus constructed for a voltage of 110 volts can at the best only be employed on a circuit having a voltage of from 100 to 125 volts and can not be used on the usual pressures of I50 and 220 volts. Now, it is often the case that in different towns or districts systems of different voltages are in use and sometimes a number of houses have separate generating plants. Physicians, hairdressers and such persons are, therefore, obliged to install suitable apparatus for all voltages or in each case to switch in suitable series resistances. The switching in of such regulating resistances necessitates a number of mechanical devices the successful manipulation of which can not be expected from a non-technical person. There must, therefore, be two circuits in the apparatus in order to economically cool or heat air, namely, the motor circuit and the heater circuit, and the electrical conditions of both these circuits must at the same time be suited to the different voltages. Consequently, there must be a series resistance in the motor circuit and a heater wire corresponding to the particular voltage in the heater circuit. If for example one of the handles is operated so that a series resistance for 220 volts is inserted in the motor circuit and a heater Wire for 150 volts is placed in the heater circuit, this heating resistance will be burned out.

According to the present invention, thehand operation is made as simple as possible and the danger of a mistake obviated. A series of light removable carriers for the heater wires are provided for the air outlet. Each carrier consists on its interior of a three pole contact. In the case of a heater which requires a higher voltage than is necessary for the motor two of these three contacts are plugs 'oined to the two ends of a heater suitable or the voltage in use, while the third contact is connected with one end of a regulating resistance which is not used as a heater and is of the smallestsize and whose other end is joined to one end of the heater wire. However, for a heater taking the normal terminal voltage of the motor, the contact for the regulating resistance is short circuited on to the plug at one end of the heater wire. These three contacts on the heater correspond to three sockets on the fixed part of the heating apparatus on the motor casing. Two of these sockets are connected to the poles of the mains and the third to one of the motor terminals.

The accompanying drawings illustrate one form of construction according to the invention.

Figure 1 shows the compressor in longitudinal section; Fig. 2 shows a heater element for pressures higher than the normal voltage of the motor; Fig. 3 shows a heater element for pressures equal to the normal terminal voltage of the motor. The diagrams of connections in Figs. 4 and 5 illustrate the circuits which exist as soon as the heater elements illustrated in Figs. 2 and 3 are inserted in the outlet pipe of the compressor and the circuits closed.

Referring to Fig. l, a is the casing of the air compressor and b the motor with the blades a mounted on its shaft. Accordin to the invention the three sockets d, e, ,5 are arranged in the outlet pipe of the compressor. The sockets d and e are connected to the conductors g and k which are joined to the mains at a convenient place on the casing by means of a switch while the socket f is connected to a terminal of the motor' through conductor 2'.

There may be as many heater elements of the kind shown in Fig. 2 as the number of different voltages of supply higher than the normal voltage of the motor to be expected. In the heater element illustrated in this figure, the plug is is joined with one end of the heater wire Z and the plug m is connected to the other end of said wire, while the series resistance 0, which is attached to the contact plate n, has its end p electrically connected with the plug m through the conductor 9. The series resist ance 0 is made as small as possible without impairing its capacity to limit the value of the current as required. Said resistance is of the short circuited metal plate 9*.

not used as a heater but serves merely; to cut down the strength of the current iwhich reaches the real heater and its value is lmown.

In'Fig. 3, the terminals is and m are joined to the end of the-heater wire l which is made of such a size that with the normal terminal voltage of the motor it is sulficiently heated while the contact late a is directly connected to the plug on y means The method of operation of the above described arrangement'is as follows :If the operator comes to a house with a main voltage of 220 volts, for instance, he takes from his apparatus box a heater element marked 220 volts and inserts it in the ordinary shown in Fig. 2. When this heater element is.

pushed in, and the contacts closed as stated, the circuits will be as shown in Fig. 4:. If in starting the air compressor, the switch .9 is employed, then the circuit from the mains through series resistance 0-and motor 6 is first closed. The turning of the switch another notch closes the circuit through the heater Z the voltage of the current having been reduced the requisite degree by the resistance in the motor circuit which is closed first. In this case, therefore, the heater wire Z of the correct dimensions is placed in the heater circuit and a proper series resistance according to the terminal voltage of the motor is inserted in the motor circuit.

It now the operator comes across a house inwhich the voltage is that for which the motor is designed, for instance a pressure of 110 volts, he uses the heater element marked 110 volts which .in this case isponstructed as shown in Fig. 3. In this case, also, the

two terminals k and m of the heater wire Z are connected to the mains. The terminals at and m which in the other heater elements are joined on to a suitable series resistance are in this case short circuited. It follows that when the heater as shown in Fig. 3 is "employed, the circuits are as illustrated in 'Fig. 5, being similar to those shown in Fig. i'except that the resistance 0 is omitted. It will be observed that asillustrated in Figs. 4: and 5, there is a motor circuit, which includes the resistance element 0, when one s used, and a secondary circuit including the heater element, the witch a being adapted to close said circuits in the order mentloned, whereby the fan will be started before the heater circuit is closed.

Having thus described my invention, what I claim as newand desire to secure by Letters Patent of the United States is:

1. The combination with a fan of a motor for driving the same, a fan casing having three-electric contacts therein, two of said contacts 'beingconnected to a source of electricity and the third contact connected to one terminalcf the motor, and a plurality of removable heater elements adapted to be used interchangeably, each one having three contacts corresponding to those in the casing, and each'of said elements being provided with a heater wire having its opposite ends connected to two of the heater contacts, substantially as and for the purpose described.

2. The combination with a fan, of a motor for driving the same, a fan-casing having three electric contacts arranged in its outlet,

two of said contacts being connected with a source of electricity and the third contact connected to one terminal of the motor, and a removable heater element having three contacts corresponding with those in the outlet of the casing, said element being provided with a heater wire having its opposite ends connected to two of the heater contacts, and a resistance element carried by the heater element and having its opposite ends connected respectively to the third heater contact and to the heater wire.

3. The combination with a fan, of a motor for driving the same, a fan casing having three electric contacts therein, two of said contacts being connected to a source of electricity and the third contact connected to one terminal of the motor, and a plurality of removable heater elements adapted to be used interchangeably, each one having three contacts corresponding to those in the easing, and each of said elements being provided with a heater, wire connected to two of the heater contacts, and a resistance element carried by the heater element and adapted to reduce a current of higher voltage to the normal terminal voltage of the motor. I

In testimony whereof I atiiX my signature, in presence of two witnesses.

, AUGUST SOHAEFFER.

Witnesses FREDERICH CARL WENTZEL, MAX HERMANN Fnorrnnn. 

